The current-voltage characteristics of Au/lowdoped n-GaAs Schottky diodes were determined at various temperatures in the range of 77-300 K. The estimated zero-bias barrier height and the ideality factor assuming thermionic emission (TE) show a temperature dependence of these parameters. While the ideality factor was found to show the T 0 effect, the zero-bias barrier height was found to exhibit two different trends in the temperature ranges of 77-160 K and 160-300 K. The variation in the flat-band barrier height with temperature was found to be −(4.7 ± 0.2) × 10 4 eVK −1 , approximately equal to that of the energy band gap. The value of the Richardson constant, A * * , was found to be 0.27 A cm −2 K −2 after considering the temperature dependence of the barrier height. The estimated value of this constant suggested the possibility of an interfacial oxide between the metal and the semiconductor. Investigations suggested the possibility of a thermionic field-emission-dominated current transport with a higher characteristic energy than that predicted by the theory. The observed variation in the zero-bias barrier height and the ideality factor could be explained in terms of barrier height inhomogenities in the Schottky diode.

Tin Selenide (SnSe) thin films were prepared from the pulverized compound material by thermal evaporation method, to study the effect of film thickness on its structural, and optical properties. The different thicknesses of SnSe thin films, from 150 nm to 500 nm, were grown on glass substrate held at room temperature. X-ray diffraction, atomic force microscopy, transmission measurement, and four-point probe method were used to characterize the thin films. The optical transmission spectra suggests, the energy band gap decreases with increasing the film thickness. The electrical resistivity shows that the films were semi-conducting in behavior having p-type conductivity.

Thin films of tin selenide (SnSe) were deposited on sodalime glass substrates, which were held at different temperatures in the range of 350-550 K, from the pulverized compound material using thermal evaporation method. The effect of substrate temperature (T s ) on the structural, morphological, optical, and electrical properties of the films were investigated using x-ray diffraction analysis (XRD), scanning electron microscopy (SEM), transmission measurements, and Hall-effect characterization techniques. The temperature dependence of the resistance of the films was also studied in the temperature range of 80-330 K. The XRD spectra and the SEM image analyses suggest that the polycrystalline thin films having uniform distribution of grains along the (111) diffraction plane was obtained at all T s . With the increase of T s the intensity of the diffraction peaks increased and well-resolved peaks at 550 K, substrate temperature, were obtained. The analysis of the data of the optical transmission spectra suggests that the films had energy band gap in the range of 1.38-1.18 eV. Hall-effect measurements revealed the resistivity of films in the range 112-20 Ωcm for films deposited at different T s . The activation energy for films deposited at different T s was in the range of 0.14 eV-0.28 eV as derived from the analysis of the data of low-temperature resistivity measurements.

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Schottky diodes have been fabricated by depositing Au on n-type CdSe thin films using the thermal evaporation technique, and their properties have been investigated by current-voltage and capacitance-voltage measurements. At room temperature, the characteristics obey the pure thermionic emission theory and the barrier height has been found to be 0.63 eV. The barrier heights decrease, while ideality factors increase with decrease in temperature. Further, the activation energy plot does not provide the expected Richardson constant and barrier height values. The abnormal behavior of the barrier heights and the ideality factors with respect to temperature as well as the difference between the barrier heights measured from I-V and those from C-V or flat band have been explored on the basis of barrier height inhomogeneities.